Underwater soil erosion prevention system

Abstract

An underwater soil erosion prevention system has a generally rectangular length of material folded at regularly spaced intervals at an angle generally perpendicular to the longitudinal axis of the rectangular length of material, thereby forming sheets. Each sheet contains slits which are generally perpendicular to the fold. The slits begin above the bottom edge of the sheet and terminate below the top edge of the sheet. The sheets contain openings sized to snugly receive an anchor line on either side. To aid in deploying the soil erosion prevention system, an inflatable rollable array with a receiving valve is provided. The array can be rolled together with the underwater soil erosion prevention system, and when ready for deployment, a fluid is controllably inserted into the array through the receiving valve, thereby causing the array and system to unroll. Alternatively, the underwater soil erosion prevention system can be releasably attached to a frame mechanism to facilitate deployment underwater.

What is claimed is: 
     
       1. An underwater soil erosion prevention system comprising: a generally rectangular length of material having at least two folds, each fold being generally perpendicular to the longitudinal axis of the rectangular length of material;   wherein said folds form a plurality of successive sheets in the rectangular length of material;   wherein one of the folds defines a top edge of two successive sheets and a successive fold defines a bottom edge of two successive sheets such that the portion of the rectangular length of material between two successive folds comprises a single sheet;   wherein the top edge of each sheet is substantially parallel to the bottom edge of the same sheet;   wherein each sheet contains at least one slit, said slit beginning above the bottom edge of the sheet and terminating below the top edge of the sheet; and   wherein said slit is generally perpendicular to the fold.   
     
     
       2. The underwater soil erosion prevention system of claim 1 wherein said rectangular length of material comprises a multilayered thin film polypropylene material having a specific gravity of less than 1.0 g/cm 3 . 
     
     
       3. The underwater soil erosion prevention system of claim 1 wherein said multilayered thin film polypropylene material has a specific gravity between 0.62 g/cm 3  and 0.69 g/cm 3 . 
     
     
       4. The underwater soil erosion prevention system of claim 1 wherein the rectangular length of material comprises polypropylene about 1 mil to 10 mils thick. 
     
     
       5. The underwater soil erosion prevention system of claim 1 wherein the rectangular length of material comprises polypropylene about 2.4 mils thick. 
     
     
       6. The underwater soil erosion prevention system of claim 1 wherein the rectangular length of material comprises material with a specific gravity of less than 1.0 g/cm 3 . 
     
     
       7. The underwater soil erosion prevention system of claim 1 wherein each sheet comprises: a first material which has a specific gravity greater than 1.0 g/cm 3  ;   wherein said sheets have a second material with a specific gravity less than 1.0 g/cm 3  attached substantially near each top edge; and   wherein the sheets bearing the second material are substantially buoyant underwater.   
     
     
       8. The underwater soil erosion prevention system of claim 1 wherein each successive sheet contains at least one aligned opening situated to receive snugly a line. 
     
     
       9. The underwater soil erosion prevention system of claim 1 wherein the angle formed between successive sheets is less than three degrees. 
     
     
       10. The underwater soil erosion prevention system of claim 1 wherein the distance between the bottom edges of successive sheets is about two inches. 
     
     
       11. The underwater soil erosion prevention system of claim 1 wherein each sheet contains a plurality of slits, wherein the slits are about one inch apart. 
     
     
       12. A method of deploying an underwater soil erosion prevention system, comprising the steps of: releasably attaching a frame sized to extend substantially around the periphery of an unfolded, unrolled underwater soil erosion prevention system, wherein said underwater soil erosion prevention system comprises   a generally rectangular length of material having at least two folds, each fold being generally perpendicular to the longitudinal axis of the rectangular length of material;   wherein said folds form a plurality of successive sheets in the rectangular length of material;   wherein one of the folds defines a top edge of two successive sheets and a successive fold defines a bottom edge of two successive sheets such that the portion of the rectangular length of material between two successive folds comprises a single sheet;   wherein the top edge of each sheet is substantially parallel to the bottom edge of the same sheet;   wherein each sheet contains at least one slit, said slit beginning above the bottom edge of the sheet and terminating below the top edge of the sheet;   wherein said slit is generally perpendicular to the fold positioning the combined frame and underwater soil erosion prevention in a place where soil erosion is to be prevented;   positioning the underwater soil erosion prevention system;   anchoring the underwater soil erosion prevention system; and   unattaching the frame.